Device for cooling



Feb. 5, 1929.

P. SCHLUMBOHM DEVICE FOR COOLING Filed Feb. 13, 1928 I N V EN TOR. l. finhlumbohm BY 94 ifTTo l j Patented i-6b. 5, 1929.

UNITED STA-"t es v 1,700,813 PATENT OFFICE.

PETER SCHLUMBOHM, 0F BERLIN, GERMANY.

DEVICE FOR COOLING.

Application filed February 13, 1928, Serial No. 254,045, and in Germany February 15, 1927.

The invention relates to a device for cooling articles by Incans'of solutions of freezing salts. With the known devices of this kind results were uncertain. because insufficient account was taken of thecharacteristics of this method of producing cooling effects.

The invention is based upon the proper consideration of the peculiarities of this method of cooling. The device according to the invention is characterized by an air and water-tight receptacle containing a pre-determined amount of the dry freezing salts, the receptacle forming at the same time'the storage vessel for the salts and the cooling vessel for receiving the salt solution and the article to be cooled and being so dimensioned that the volume of its interior is equal to the sum of the volumes of the article to be cooled and of the salt solution, formed when the exact quantity of water required for dissolving the salt is poured in.

Accordingly a cooling receptacle of definite volume is to beobtained for definite cooling purposes and a pie-determined quantity of salt added. This predetermined amount of salt also requires a definite quantity of water. If the amount of water is too small, all the salt is not dissolved, and if it is too large. the excess of water has also to be cooled. Both defects affect the cooling action.

These facts have not been taken into consideration in the known devices. For instance devices have been proposed in which a bottle to be cooled was placed in too large a receptacle and was at the same time wrapped round with packing material mixed with freezing salt. This known device required a considerable excess of water. It was not only necessary to cool this water at the same time, but also the packing material and the excessively large receptacle.

These disadvantages are obviated by the invention.

The purpose of this invention is substantially assisted by making the cooling receptacle of paper or pasteboard impregnated so as to he air and water-tight. The air-tight impregnation provides the further advantage of the invention, that a separate packing container is not required for the generally hygroscopic freezing salts (ammoniumnitrate) and similar substances. In addition to the air-tightness, the lightness of the pasteboai'd is also particularly advantageous.

In the accompanying drawing, I have indicated one form of my invention, the figure showing in cross-sectional elevation an ad- 1 kg. glass of specific heat 0'2 and contains about 750 com. liquid the specific heat of which may be considered as equal to 1. For calori metric calculations a good practical approximation is to consider the filled bottle as equivalent to a litre of water (1000X02 plus 750 1). For practical purpose it is necessary to cool this bottle by 15 to 20 degrees Celsius, i. e. to take from it 15 to 20 Kcal. For this purpose if ammonium-nitrate is used as freezing salt 700 grs. of the latter are required. These 7 00 grs. salt give with the 700 com. water a saturated solution of 1100 com. This volume of 1100 ccm. solution plus 1230 ccm. volume of the bottle give together 2330 ccm. volume. As the height of the receptacle is determined by the standard height of the. bottle, this gives an internal diameter of about 100 com. diameter with a height of 325 mm., corresponding to a volume of about 2540 ccm., constituting an addition of about 10% as compared with the calculated'volume of 2330 com. to enable the freezing solution to be stirred round by the immersed bottle. A receptacle of this kind may receive several doses of freezing salt.

The cover of the receptacle may be constructed in the form of a measuring device for the quantity of water to be poured in. as it is important to measure 01f exactly the water required for making the satured solution.

Paper and pasteboard are to be recom' mended as material for the cooling receptacle.

article to be cooled, and being so dimensioned that the volume of its interior is equal to the sum of the volumes of the article to be cooled and of the salt solution, formed when the exact quantity of water required for dissolving the salt is poured in.

2. A device for cooling by means of solutions of freezing salts, comprising an air and water-tight receptacle containing a pre-determined amount of the dry freezing salts and made of impregnated pasteboard, which is air and water-tight, this receptacle forming at the same time the storage vessel for the salts and the cooling vessel for-receiving the salt solution and the article to be cooled, and being so dimensioned that the volume of its interior is equal to the sum of the volumes of the article to be cooled and of the salt solution, formed when the exact quantity of water required for dissolving the salt is 20 poured in. In testimony whereof I afiix my signature.

DR. PETER SCHLUMBOHM. 

